<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>CSS Demo</title>

  <link rel="stylesheet" href="styles.css">
  <!-- <style>
    body {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    main {
      max-width: 800px;
      margin: 0 auto;
    }
    h1 {
      text-align: center;
      font-size: 2.5rem;
      color: blue;
    }
    img {
      width: 100%;
    }
    span {
      color: red;
      font-weight: bold;
    }
  </style> -->

</head>
<body>
  <main>

    <section>
      <img src="https://images.unsplash.com/photo-1537498425277-c283d32ef9db?ixlib=rb-4.0.3&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=2356&h=600&q=80" alt="">
    </section>
    <section>
      <h1>hello world</h1>
    </section>

    <section class="skyblue">
      <h2>
        CSS
        <button>Contact us</button>
      </h2>
    </section>

    <section class="content">
      <p>
        Cascading Style Sheets (<code>CSS</code>) is a style sheet language used for describing the presentation of a document written in a markup language such as HTML or XML <sub>(including XML dialects such as SVG, MathML or XHTML)</sub>.<sup>[1]</sup> CSS is a cornerstone technology of the World Wide Web, alongside HTML and JavaScript.<sup>[2]</sup>
      </p>

      <!-- <div class="demo">
        <div class="dialog">
          <button>hi</button>
        </div>
      </div> -->

      <p>
        <code>CSS</code> is designed to enable the separation of content and presentation, including layout, colors, and fonts.<sup>[3]</sup> This separation can improve content accessibility; provide more flexibility and control in the specification of presentation characteristics; enable multiple web pages to share formatting by specifying the relevant CSS in a separate .css file, which reduces complexity and repetition in the structural content; and enable the .css file to be cached to improve the page load speed between the pages that share the file and its formatting.
      </p>
      <p>
        Separation of formatting and content also makes it feasible to present the same markup page in different styles for different rendering methods, such as on-screen, in print, by voice <sub>(via speech-based browser or screen reader)</sub>, and on Braille-based tactile devices. CSS also has rules for alternate formatting if the content is accessed on a mobile device.<sup>[4]</sup>
      </p>
      <p id="name">
        The name cascading comes from the specified priority scheme to determine which style rule applies if more than one rule matches a particular element. This cascading priority scheme is predictable.
      </p>
      <p>
        The <code>CSS</code> specifications are maintained by the <span>World Wide Web</span> Consortium <sub>(W3C)</sub>. Internet media type <sub>(MIME type)</sub> text/css is registered for use with CSS by RFC 2318 <sub>(March 1998)</sub>. The W3C operates a free CSS validation service for CSS documents.<sup>[5]</sup>
      </p>
      <p class="skyblue">
        In addition to <strong>HTML</strong>, other markup languages support the use of CSS including <strong>XHTML</strong>, plain <strong>XML</strong>, <strong>SVG</strong>, and <strong>XUL</strong>.
      </p>
    </section>

    <section class="navbar">
      <div class="navbar">
        <button><a href="/">home</a></button>
        <a href="/news.html"><button>news</button></a>
        <a href="/mine">mine</a>
      </div>
    </section>

  </main>
</body>
</html>
